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SUMMARY:Making rubber gloves - Alexander F. Routh  CEB and BP Institute ( 
 BP Institute and Bob Groves\, BP Institute visitor)
DTSTART:20200430T103000Z
DTEND:20200430T113000Z
UID:TALK140695@talks.cam.ac.uk
CONTACT:Catherine Pearson
DESCRIPTION:Thin rubber gloves are used extensively in medicine and lab se
 ttings. Over 300 billion are manufactured each year from either natural la
 tex or synthetic nitrile rubber. The manufacturing process involves using 
 a hand shaped mould – called a former. This is dipped into a concentrate
 d calcium nitrate solution\, dried and then dipped into an aqueous colloid
 al dispersion of the polymer. Diffusion of electrolyte into the latex bath
  causes aggregation onto the former and generation of a wet gel. After a s
 et time in the latex bath the former is dried\, washed and then the glove 
 is removed.\nWe model the formation of the wet gel to predict the thicknes
 s of the glove as a function of dipping time. A simple diffusional model w
 orks well at short dwell times\, but at longer times the wet gel growth is
  reduced\, which we ascribe to a limited quantity of electrolyte and a rea
 ction between calcium ions and surfactant.\n\nContrary to experimental obs
 ervation\, typical flow velocities are predicted to dominate diffusional t
 ransport. The wet gel restricts flow so that diffusion is dominant close t
 o the former and further away flow dominates. We include a flow term in th
 e model for wet gel growth\, match the two solutions and predict the wet g
 el size. We have built a flow tank to investigate wet gel growth and compa
 re our predictions with the experiments.\n
LOCATION:Open Plan Area\, BP Institute\, Madingley Rise CB3 0EZ
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